Congeners are impurities that are byproducts of the fermentation process. Our bodies treat them as a poison, and a headache is a very common symptom of poison processing. That said, different people may be better or worse at metabolizing and flushing these toxins. It is widely believed that because cheaper alcoholic beverages begin with lower-quality ingredients and hence more congeners are likely to be produced at the fermentation stage.
2. Lack of distillation and filtration
Each time liquor goes through the distilling process, more and more congeners and impurities (which may cause headaches) are removed. Tito’s, a quality vodka, is distilled six times. If you are buying bottom-shelf vodka, you’ll be lucky if it was distilled twice. Filtration is another way that vodka brands attempt to clear out impurities. Bottom-self brands typically do the minimum for filtration.
3. Darker Spirits
Darker spirits, like brandy, whisky, and cognac, tend to have higher concentrations of congeners than their clear brethren—vodka, gin, or white rum. (Tequila is an exception.) This isn’t a cheap vs. expensive thing, though, it’s simply a difference in the distillation process. The mark of a good vodka is no flavor, whereas whiskey should have a distinct flavor and congeners are an important part of that equation.
4. The Red Wine Puzzle
The comparative price of a wine doesn’t seem to be a factor, as every extremely expensive wines can cause Red Wine Headache. The leading cause seems to be histamines, which are present in grape skins. White wine, which is made without the skins, has far fewer histamines in it, and is much less likely to cause a headache. However, the histamine content can change from vintage to vintage, so a wine that didn’t give you a headache last year can lead to a pounding headache this year.
Another factor is sugar content – cheap wines are often very sugary. Adding sugar to grape juice can accelerate the fermentation process, but this typically leads to an inferior type of alcohol. Also, the added sugar will cause a spike in your blood-sugar. When it comes crashing down, headaches are a common side effect. Liqueurs, candy-like spirits, and very sweet cocktails may have the same effect.
Alcohol is a diuretic, which means you need to go to the bathroom more often and hence less water for your internal organs. Your organs then try to borrow water from anywhere they can, including your brain. As your brain dehydrates, it slightly contracts. This strains the connective tissue that holds your brain in your skull, resulting in a screaming headache. In other words, stay hydrated as you drink.
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